EP2311111B1 - Organic electroluminescence device - Google Patents

Description

The present invention relates to phosphorescent organic electroluminescent devices containing fluorene and spirobifluorene derivatives as matrix materials.

Organic semiconductors are being developed for a variety of electronic applications. The construction of organic electroluminescent devices (OLEDs) in which these organic semiconductors are used as functional materials is described, for example, in US Pat US 4539507 . US 5151629 . EP 0676461 and WO 98/27136 described. However, further improvements are needed. Thus, there is still room for improvement, especially with regard to the lifetime, the efficiency and the operating voltage of organic electroluminescent devices. Furthermore, it is necessary that the compounds have a high thermal stability and a high glass transition temperature and can sublime undecomposed.

Especially in the case of phosphorescent electroluminescent devices, improvements of the abovementioned properties are still required. In particular, there is a need for improvement in matrix materials for phosphorescent emitters, which at the same time lead to good efficiency, a long service life and low operating voltage. Especially the properties of the matrix materials are often limiting for the life and the efficiency of the organic electroluminescent device.

In the prior art, carbazole derivatives, e.g. B. bis (carbazolyl) biphenyl, as matrix materials used see eg WO 2008/086851 , There is still room for improvement here, especially with regard to the service life and the glass transition temperature of the materials.

Furthermore, ketones ( WO 04/093207 ), Phosphine oxides and sulfones ( WO 05/003253 ) are used as matrix materials for phosphorescent emitters. Especially with ketones low operating voltages and long lifetimes are achieved. Here still exists In particular, there is a need for improvement in terms of efficiency and compatibility with metal complexes containing ketoketonate ligands, for example, acetylacetonate.

Furthermore, metal complexes, for example BAlq or bis [2- (2-benzothiazole) phenolate] zinc (II), are used as matrix materials for phosphorescent emitters. There is still room for improvement here, especially with regard to the operating voltage and the chemical stability. Pure organic compounds are often more stable than these metal complexes. Thus, some of these metal complexes are sensitive to hydrolysis, which makes it difficult to handle the complexes.

In particular, there is still room for improvement in matrix materials for phosphorescent emitters, which at the same time lead to high efficiencies, long lifetimes and low operating voltages and which are also compatible with phosphorescent emitters which carry ketoketonate ligands.

Surprisingly, it has been found that fluorene derivatives and corresponding heterocyclic derivatives which are substituted by triazine or other electron-poor nitrogen heterocycles, in particular spirobifluorene derivatives, are very suitable as matrix materials for phosphorescent emitters and in this use lead to OLEDs which simultaneously have high efficiencies, long lifetimes and low yields Operating voltages, even with phosphorescent emitters containing ketoketonate ligands.

In the US 6,229,012 and US 6,225,467 For example, the use of fluorene derivatives substituted with triazine groups is disclosed as an electron transport material in OLEDs. However, it is not apparent from the application that these materials are also suitable as matrix materials for phosphorescent emitters.

In the WO 05/053055 describes the use of triazine derivatives, in particular of spirobifluorene derivatives which are substituted with triazine groups, as hole-blocking material in phosphorescent OLEDs disclosed. However, it is not apparent from the application that these materials are also suitable as matrix materials for phosphorescent emitters.

Lee Lee et al., Thin Solid Films, 2008, 516 (15), 5062-5068 discloses the use of pyrimidine-substituted spirofluorene as light-emitting materials in OLEDs.

1. (A) mindestens eine phosphoreszierende Verbindung, und
2. (B) mindestens eine Verbindung gemäß Formel (1) oder Formel (2),
   
   
   wobei für die verwendeten Symbole und Indizes gilt:

   Ar

   ist bei jedem Auftreten gleich oder verschieden eine Heteroarylgruppe, ausgewählt aus der Gruppe bestehend aus Triazin, Pyrazin, Pyrimidin, Pyridazin, Pyridin, Pyrazol, Imidazol, Oxazol, Oxadiazol oder Thiazol, welche jeweils mit einer oder mehreren Gruppen R¹ substituiert sein kann;

   X

   ist bei jedem Auftreten gleich oder verschieden eine Gruppe gemäß Formel (3), wobei die gestrichelte Bindung jeweils die Bindung an die beiden Benzolringe andeutet:

   

   oder X ist gleich oder verschieden bei jedem Auftreten eine bivalente Brücke, ausgewählt aus B(R¹), C(R¹)₂, Si(R¹)₂, C=C(R¹)₂, O, S, S=O, SO₂, N(R¹), P(R¹) und P(=O)R¹;

   R¹

   ist bei jedem Auftreten gleich oder verschieden H, D, F, Cl, Br, I, CHO, N(Ar¹)₂, C(=O)Ar¹, P(=O)(Ar¹)₂, S(=O)Ar¹, S(=O)₂Ar¹, CR²=CR²Ar¹, CN, NO₂, Si(R²)₃, B(OR²)₂, B(R²)₂, B(N(R²)₂)₂, OSO₂R², eine geradkettige Alkyl-, Alkoxy- oder Thioalkoxygruppe mit 1 bis 40 C-Atomen oder eine geradkettige Alkenyl-oder Alkinylgruppe mit 2 bis 40 C-Atomen oder eine verzweigte oder cyclische Alkyl-, Alkenyl-, Alkinyl-, Alkoxy- oder Thioalkoxygruppe mit 3 bis 40 C-Atomen, die jeweils mit einem oder mehreren Resten R² substituiert sein kann, wobei eine oder mehrere bevorzugt nicht benachbarte CH₂-Gruppen durch R²C=CR², C=C , Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C=O, C=S, C=Se, C=NR², P(=O)(R²), SO, SO₂, NR², O, S oder CONR² ersetzt sein können und wobei ein oder mehrere H-Atome durch D, F, Cl, Br, I, CN oder NO₂ ersetzt sein können, oder ein aromatisches oder heteroaromatisches Ringsystem mit 5 bis 60 aromatischen Ringatomen, das jeweils durch einen oder mehrere Reste R² substituiert sein kann, oder eine Aryloxy- oder Heteroaryloxygruppe mit 5 bis 60 aromatischen Ringatomen, die durch einen oder mehrere Reste R² substituiert sein kann, oder eine Kombination dieser Systeme; dabei können zwei oder mehrere benachbarte Substituenten R¹ auch miteinander ein mono- oder polycyclisches, aliphatisches oder aromatisches Ringsystem bilden;

   Ar¹

   ist bei jedem Auftreten gleich oder verschieden ein aromatisches oder heteroaromatisches Ringsystem mit 5 bis 30 aromatischen Ringatomen, das mit einem oder mehreren Resten R² substituiert sein kann; dabei können auch zwei Reste Ar¹, welche an dasselbe Stickstoff-, Phosphor- oder Boratom binden, durch eine Einfachbindung oder eine Brücke, ausgewählt aus B(R²), C(R²)₂, Si(R²)₂, C=O, C=NR², C=C(R²)₂, O, S, S=O, SO₂, N(R²), P(R²) und P(=O)R², miteinander verknüpft sein;

   R²

   ist bei jedem Auftreten gleich oder verschieden H, D oder ein aliphatischer, aromatischer und/oder heteroaromatischer Kohlenwasserstoffrest mit 1 bis 20 C-Atomen, in dem auch H-Atome durch D oder F ersetzt sein können; dabei können zwei oder mehrere benachbarte Substituenten R² auch miteinander ein mono- oder polycyclisches, aliphatisches oder aromatisches Ringsystem bilden;

   n

   ist 0 oder 1;

   m

   ist 0, 1, 2 oder 3;

   o

   ist 0, 1, 2, 3 oder 4, wenn n = 0 ist und ist 0, 1, 2 oder 3, wenn n = 1 ist.

The invention thus relates to an organic electroluminescent device comprising at least one emitting layer

1. (A) at least one phosphorescent compound, and
2. (B) at least one compound according to formula (1) or formula (2),
   
   
   where the symbols and indices used are:

   Ar

   is identical or different at each occurrence, a heteroaryl group selected from the group consisting of triazine, pyrazine, pyrimidine, pyridazine, pyridine, pyrazole, imidazole, oxazole, oxadiazole or thiazole, which may be substituted in each case with one or more groups R ¹ ;

   X

   is the same or different at each occurrence a group according to formula (3), wherein the dashed bond in each case indicates the bond to the two benzene rings:

   

   or X is the same or different at each occurrence as a divalent bridge selected from B (R ¹ ), C (R ¹ ) ₂ , Si (R ¹ ) ₂ , C = C (R ¹ ) ₂ , O, S, S = O, SO ₂ , N (R ¹ ), P (R ¹ ) and P (= O) R ¹ ;

   R ¹

   is identical or different at each occurrence H, D, F, Cl, Br, I, CHO, N (Ar ¹ ) ₂ , C (= O) Ar ¹ , P (= O) (Ar ¹ ) ₂ , S (= O) Ar ¹ , S (= O) ₂ Ar ¹ , CR ² = CR ² Ar ¹ , CN, NO ₂ , Si (R ² ) ₃ , B (OR ² ) ₂ , B (R ² ) ₂ , B ( N (R ² ) ₂ ) ₂ , OSO ₂ R ² , a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl -, alkenyl, alkynyl, alkoxy or Thioalkoxygruppe having 3 to 40 carbon atoms, which may be substituted in each case with one or more radicals R ² , wherein one or more preferably non-adjacent CH ₂ groups by R ² C = CR ² , C = C, Si (R ² ) ₂ , Ge (R ² ) ₂ , Sn (R ² ) ₂ , C = O, C = S, C = Se, C = NR ² , P (= O) ( R ² ), SO, SO ₂ , NR ² , O, S or CONR ² may be replaced and wherein one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO ₂ , or a aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, each may be substituted by one or more radicals R ² , or an aryloxy or heteroaryloxy group having 5 to 60 aromatic ring atoms which may be substituted by one or more radicals R ² , or a combination of these systems; two or more adjacent substituents R ^{1 may} also together form a mono- or polycyclic, aliphatic or aromatic ring system;

   Ar ¹

   is identical or different at each occurrence an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which is substituted with one or more radicals R ² can be; two radicals Ar ¹ which bind to the same nitrogen, phosphorus or boron atom can also be replaced by a single bond or a bridge selected from B (R ² ), C (R ² ) ₂ , Si (R ² ) ₂ , C = O, C = NR ² , C = C (R ² ) ₂ , O, S, S = O, SO ₂ , N (R ² ), P (R ² ) and P (= O) R ² , linked together be;

   R ²

   is identical or different at each occurrence H, D or an aliphatic, aromatic and / or heteroaromatic hydrocarbon radical having 1 to 20 carbon atoms, in which H atoms may also be replaced by D or F; two or more adjacent substituents R ^{2 may} also together form a mono- or polycyclic, aliphatic or aromatic ring system;

   n

   is 0 or 1;

   m

   is 0, 1, 2 or 3;

   O

   is 0, 1, 2, 3 or 4 when n = 0 and is 0, 1, 2 or 3 when n = 1.

An organic electroluminescent device is understood to mean a device which contains the anode, cathode and at least one emitting layer, which is arranged between the anode and the cathode, wherein at least one layer between the anode and the cathode contains at least one organic or organometallic compound. In this case, at least one emitting layer contains at least one phosphorescent emitter and at least one compound of the above-mentioned formula (1) or (2). An organic electroluminescent device need not necessarily contain only layers composed of organic or organometallic materials. So it is also possible that one or more layers contain inorganic materials or are constructed entirely of inorganic materials.

A phosphorescent compound in the context of this invention is a compound which at room temperature luminescence from an excited Shows state with higher spin multiplicity, ie a spin state> 1, in particular from an excited triplet state. For the purposes of this invention, in particular all luminescent iridium and platinum compounds are to be regarded as phosphorescent compounds.

An aryl group in the sense of this invention contains at least 6 C atoms; For the purposes of this invention, a heteroaryl group contains at least 2 C atoms and at least 1 heteroatom, with the proviso that the sum of C atoms and heteroatoms gives at least 5. The heteroatoms are preferably selected from N, O and / or S. Here, under an aryl group or heteroaryl either a simple aromatic cycle, ie benzene, or a simple heteroaromatic cycle, for example pyridine, pyrimidine, thiophene, etc., or a fused aryl or heteroaryl group, for example naphthalene, anthracene, pyrene, quinoline, isoquinoline, etc., understood.

An aromatic ring system in the context of this invention contains at least 6 C atoms in the ring system. A heteroaromatic ring system in the sense of this invention contains at least 2 C atoms and at least one heteroatom in the ring system, with the proviso that the sum of C atoms and heteroatoms gives at least 5. The heteroatoms are preferably selected from N, O and / or S. An aromatic or heteroaromatic ring system in the sense of this invention is to be understood as meaning a system which does not necessarily contain only aryl or heteroaryl groups but in which also several aryl or heteroaryl groups a short, non-aromatic moiety (preferably less than 10% of the atoms other than H), e.g. B. a sp ³ - or sp ² -hybridized C, N or O atom, may be interrupted. For example, systems such as 9,9'-spirobifluorene, 9,9-diaryl fluorene, triarylamine, diaryl ether, stilbene, benzophenone, etc. are also to be understood as aromatic ring systems in the context of this invention. Likewise, an aromatic or heteroaromatic ring system is understood as meaning systems in which a plurality of aryl or heteroaryl groups are linked together by single bonds, for example biphenyl, terphenyl or bipyridine.

In the context of the present invention, a C ₁ - to C ₄₀ -alkyl group in which also individual H atoms or CH ₂ groups can be substituted by the abovementioned groups, particularly preferably the radicals methyl, ethyl, n-propyl, i -propyl, n-butyl, i -butyl, s -butyl, t -butyl, 2-methylbutyl, n -pentyl, s -pentyl, tert- pentyl, 2-pentyl, cyclopentyl, n -hexyl, s -hexyl, t -hexyl, 2-hexyl, 3-hexyl, cyclohexyl, 2-methylpentyl, n- heptyl, 2-heptyl, 3-heptyl, 4-heptyl, cycloheptyl, 1-methylcyclohexyl, n- octyl, 2-ethylhexyl, cyclooctyl, 1-bicyclo [2,2,2] octyl, 2-bicyclo [2,2,2] octyl, 2- (2,6-dimethyl) octyl, 3- (3,7-dimethyl) octyl, trifluoromethyl, pentafluoroethyl , 2,2,2-trifluoroethyl, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl or octynyl. A C ₁ - to C ₄₀ -alkoxy group is particularly preferably understood to mean methoxy, trifluoromethoxy, ethoxy, n- propoxy, i -propoxy, n- butoxy, i- butoxy, s- butoxy, t -butoxy or 2-methylbutoxy. By an aromatic or heteroaromatic ring system having 5-60 aromatic ring atoms, which may be substituted in each case with the abovementioned radicals R and which may be linked via any positions on the aromatic or heteroaromatic, are understood in particular groups which are derived from benzene, Naphthalene, anthracene, phenanthrene, benzanthracene, pyrene, chrysene, perylene, fluoranthene, benzfluoranthene, naphthacene, pentacene, benzpyrene, biphenyl, biphenylene, terphenyl, terphenylene, fluorene, benzofluorene, dibenzofluorene, spirobifluorene, dihydrophenanthrene, dihydropyrene, tetrahydropyrene, cis- or trans Indenofluorene, cis or trans monobenzoindenofluorene, cis or trans dibenzoindenofluorene, truxene, isotruxene, spirotruxene, spiroisotruxene, furan, benzofuran, isobenzofuran, dibenzofuran, thiophene, benzothiophene, isobenzothiophene, dibenzothiophene, pyrrole, indole, isoindole, carbazole, pyridine , Quinoline, isoquinoline, acridine, phenanthridine, benzo-5,6-quinol in, benzo-6,7-quinoline, benzo-7,8-quinoline, phenothiazine, phenoxazine, pyrazole, indazole, imidazole, benzimidazole, naphthimidazole, phenanthrimidazole, pyridimidazole, pyrazine imidazole, quinoxaline imidazole, oxazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, Isoxazole, 1,2-thiazole, 1,3-thiazole, benzothiazole, pyridazine, benzopyridazine, pyrimidine, benzpyrimidine, quinoxaline, 1,5-diazaanthracene, 2,7-diazapyrene, 2,3-diazapyrene, 1,6-diazapyrene, 1,8-diazapyrene, 4,5-diazapyrene, 4,5,9,10-tetraazaperylene, pyrazine, phenazine, phenoxazine, phenothiazine, fluorubin, naphthyridine, azacarbazole, benzocarboline, phenanthroline, 1,2, 3-triazole, 1,2,4-triazole, benzotriazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2, 3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 1,3,5-triazine, 1,2,4-triazine, 1,2,3- Triazine, tetrazole, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, purine, pteridine, indolizine and benzothiadiazole.

The compounds of the formulas (1) and (2) preferably have a glass transition temperature T _G of greater than 70 ° C., more preferably greater than 90 ° C., very particularly preferably greater than 110 ° C.

In a preferred embodiment of the invention, the group X, identically or differently on each occurrence, stands for a group according to formula (3) or for a divalent bridge selected from C (R ¹ ) ₂ , Si (R ¹ ) ₂ and NR ¹ . In a particularly preferred embodiment of the invention, the group X is a group of the formula (3) or C (R ¹ ) ₂ .

wobei die verwendeten Symbole und Indizes dieselben Bedeutungen haben, wie oben beschrieben.The compound according to formula (1) is thus more preferably either a spirobifluorene derivative if the group X is a group of the formula (3) or it is a fluorene derivative if the group X is C (R ¹ ) ₂ . Also, the compound of the formula (2) is particularly preferably a spirobifluorene derivative, a fluorene derivative or a compound containing a spirobifluorene group and a fluorene group. A particularly preferred embodiment of the invention are therefore the fluorene derivatives according to the formulas (4) and (5) and the spirobifluorene derivatives according to the formulas (6) and (7),

wherein the symbols and indices used have the same meanings as described above.

The group Ar is an electron-poor heteroaromatic. Preferably, the group Ar is the same or different at each occurrence for a 6-membered heteroaromatic ring, ie for triazine, pyrazine, pyrimidine, pyridazine or pyridine, which in each case substituted by one or more radicals R ¹ can be.

In a preferred embodiment of the invention, the monovalent group Ar in compounds of the formulas (1), (2) and (4) to (7) is selected from the groups according to the following formulas (8) to (20), wherein the dashed bond each indicates the binding of the group to the fluorene or the spirobifluorene or to the corresponding heterocyclic derivative and R ^{1 has the} same meaning, as described above:

In a preferred embodiment of the invention, the divalent group Ar in compounds of the formulas (2) and (7) is selected from the groups according to the following formulas (21) to (28), wherein the dotted bonds each indicate the bond of the group to the fluorene or indicate the spirobifluorene or the corresponding heterocyclic derivative and R ^{1 has the} same meaning, as described above:

In a preferred embodiment of the invention, the group Ar contains two or three nitrogen atoms. Therefore, preferred monovalent groups Ar are the groups of the formulas (8) to (17), and preferred divalent groups Ar are the groups of the formulas (21) to (26). Most preferably, the group Ar contains three nitrogen atoms. Particularly preferred monovalent groups Ar are therefore the groups of the formulas (8) to (11), in particular the group according to formula (8), and particularly preferred bivalent groups Ar are the groups of the formulas (21) and (22), in particular the group according to formula (21).

In yet a further preferred embodiment of the invention, the radical R ¹ which is bonded to the groups of the formulas (8) to (28), identical or different at each occurrence for H, D, is a straight-chain alkyl or alkoxy group having 1 to 10 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 10 carbon atoms, each of which may be substituted by one or more radicals R ² , wherein one or more H atoms may be replaced by D or F, or a aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, each of which may be substituted by one or more radicals R ² , or a combination of these systems. In a particularly preferred embodiment of the invention, the radical R ¹ , which is bonded to the groups of the formulas (8) to (28), identical or different at each occurrence for H or D, a straight-chain alkyl group having 1 to 5 C atoms or a branched or cyclic alkyl group having 3 to 6 C-atoms which may each be substituted by one or more radicals R ² , wherein one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring system having from 5 to 25 aromatic ring atoms, each by one or more radicals R ² may be substituted, or a combination of these systems. Most preferably, the radical R ¹ which is bonded to the groups of the formulas (8) to (28), identical or different at each occurrence for H or D or for an aromatic or heteroaromatic ring system having 5 to 14 aromatic ring atoms, the each may be substituted by one or more radicals R ² , in particular phenyl, naphthyl or biphenyl, which may be substituted by one or more radicals R ² , but is preferably unsubstituted.

In yet a further preferred embodiment of the invention, the radical R ¹ , which is bonded directly to the fluorene or spirobifluorene or the corresponding heterocyclic compound, is identical or different at each occurrence for H, a straight-chain alkyl or alkoxy group having 1 to 10 C. Atoms or a branched or cyclic alkyl or alkoxy group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R ² , wherein one or more H atoms may be replaced by D or F, or an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, each of which may be substituted by one or more radicals R ² , or a combination of these systems. In a particularly preferred embodiment of the invention, the radical R ¹ , which is bonded directly to the fluorene or spirobifluorene or the corresponding heterocyclic compound, is identical or different at each occurrence for H, a straight-chain alkyl group having 1 to 5 C atoms or a branched or cyclic alkyl group having 3 to 6 C atoms, each of which may be substituted by one or more R ² radicals, where one or more H atoms may be replaced by D or F, or by an aromatic or heteroaromatic ring system comprising 5 to 25 aromatic ring atoms, which may be substituted in each case by one or more radicals R ² .

wobei die Symbole und Indizes dieselbe Bedeutung haben, wie oben beschrieben und wobei für n = 0 in der entsprechenden Position auch ein Substituent R¹ gebunden sein kann. Eine bevorzugte Ausführungsform der Verbindungen gemäß Formel (29) und (30) sind Verbindungen, in denen X für C(R¹)₂ steht.In a further preferred embodiment of the invention, the group Ar is bonded in the 2-position of the fluorine or spirobifluorene or of the corresponding heterocycle. If more than one group Ar is present, the other groups Ar are preferably attached in the 7-position and in spirobifluorene derivatives also in the 2'-position and 7'-position. Particularly preferred compounds according to formulas (1), (2) and (4) to (7) are therefore the compounds according to the formulas (29) to (32),

where the symbols and indices have the same meaning as described above and wherein for n = 0 in the corresponding position also a substituent R ¹ can be bound. A preferred embodiment of the compounds according to formula (29) and (30) are compounds in which X is C (R ¹ ) ₂ .

In a preferred embodiment of compounds according to formulas (1), (2), (4) to (7) and (29) to (32), the index m = 0, d. H. except the group Ar, no further substituent is attached to this benzene ring.

In a further preferred embodiment of compounds according to formulas (1), (2), (4) to (7) and (29) to (32), the sum of the indices n + o = 0 or 1, ie Each benzene ring is bound to a maximum of one group Ar or at most one radical R ¹ .

Preferred embodiments of the compounds according to formulas (29) to (32) are compounds in which the group Ar is a group according to the above-mentioned formulas (8) to (28).

wobei die verwendeten Symbole und Indizes die oben genannten Bedeutungen haben und weiterhin gilt, dass an jedem Benzolring n + o = 0 oder 1 ist und wobei der Rest R¹ für n = 0 und o = 1 an jeder beliebigen freien Stelle des Benzolrings gebunden sein kann. Bevorzugte Ausführungsformen für Verbindungen gemäß Formel (33) und (34) sind solche, in denen X für C(R¹)₂ steht.In a very particularly preferred embodiment of the invention, in the compounds of the formula (29) to (32), the group Ar is a group of the formula (8) or formula (21). Also particularly preferred in these compounds is m = 0 and n + o = 0 or 1 on each Benzene ring. Very particular preference is therefore given to the compounds of the formulas (33) to (36),

where the symbols and indices used have the abovementioned meanings and furthermore that on each benzene ring n + o = 0 or 1 and in which the radical R ¹ for n = 0 and o = 1 is bonded to any free point of the benzene ring can. Preferred embodiments of compounds according to formula (33) and (34) are those in which X is C (R ¹ ) ₂ .

wobei die verwendeten Symbole die oben genannten Bedeutungen haben und o gleich oder verschieden bei jedem Auftreten für 0 oder 1 steht.Particular preference is given to the spirobifluorene derivatives of the formulas (35) and (36), in particular the spirobifluorene derivative of the formula (35). Most preferably, the compounds according to formula (35) contain one or two triazine groups. The compounds of the formula (35) are therefore more preferably selected from compounds of the formulas (37), (38) and (39)

where the symbols used have the abovementioned meanings and o is the same or different at each occurrence as 0 or 1.

Examples of preferred compounds according to the formulas (1), (2), (4) to (7) and (29) to (39) are the structures (1) to (96) shown below.

The compounds according to formula (1) can be used, for example, according to the in US 6,229,012 . US 6,225,467 and WO 05/053055 be synthesized described methods. In general, metal-catalyzed coupling reactions are suitable for the synthesis of the compounds, in particular the Suzuki coupling, as shown in the following Scheme 1 using the example of triazine. Thus, a fluorene, spirobifluorene or other heterocyclic derivative, which is each substituted with a boronic acid or a boronic acid derivative, be coupled under palladium catalysis with the group Ar, which for compounds of formula (1) with a reactive leaving group and for compounds of formula (2) is substituted with two reactive leaving groups. Suitable reactive leaving groups are, for example, halogens, in particular chlorine, bromine and iodine, triflate or tosylate.

As described above, the compounds of the formulas (1) and (2) are used as matrix materials for phosphorescent emitters.

Particularly suitable as phosphorescent compounds are compounds which emit light, preferably in the visible range, with suitable excitation and also contain at least one atom of atomic number greater than 20, preferably greater than 38 and less than 84, particularly preferably greater than 56 and less than 80. Preferred phosphorescence emitters used are compounds containing copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, in particular compounds containing iridium or platinum.

wobei R¹ dieselbe Bedeutung hat, wie oben für Formel (1) und (2) beschrieben, und für die weiteren verwendeten Symbole gilt:

DCy

ist gleich oder verschieden bei jedem Auftreten eine cyclische Gruppe, die mindestens ein Donoratom, bevorzugt Stickstoff, Kohlenstoff in Form eines Carbens oder Phosphor, enthält, über welches die cyclische Gruppe an das Metall gebunden ist, und die wiederum einen oder mehrere Substituenten R¹ tragen kann; die Gruppen DCy und CCy sind über eine kovalente Bindung miteinander verbunden;

CCy

ist gleich oder verschieden bei jedem Auftreten eine cyclische Gruppe, die ein Kohlenstoffatom enthält, über welches die cyclische Gruppe an das Metall gebunden ist und die wiederum einen oder mehrere Substituenten R¹ tragen kann;

A

ist gleich oder verschieden bei jedem Auftreten ein monoanionischer, zweizähnig chelatisierender Ligand, bevorzugt ein Diketonatligand.

Particularly preferred organic electroluminescent devices contain as phosphorescent emitter at least one compound of the formulas (40) to (43),

wherein R ^{1 has the} same meaning as described above for formula (1) and (2), and for the other symbols used:

DCy

is identical or different at each occurrence, a cyclic group containing at least one donor atom, preferably nitrogen, carbon in the form of a carbene or phosphorus, via which the cyclic group is bonded to the metal, and in turn carry one or more substituents R ¹ can; the groups DCy and CCy are linked by a covalent bond;

CCy

is identical or different at each occurrence, a cyclic group containing a carbon atom through which the cyclic group is bonded to the metal and in turn may carry one or more substituents R ¹ ;

A

is the same or different at each occurrence a monoanionic, bidentate chelating ligand, preferably a diketonate ligand.

In this case, by forming ring systems between a plurality of radicals R ^{1, there may} also be a bridge between the groups DCy and CCy.

Examples of the emitters described above can be found in the applications WO 00/70655 . WO 01/41512 . WO 02/02714 . WO 02/15645 . EP 1191613 . EP 1191612 . EP 1191614 and WO 05/033244 be removed. In general, all phosphorescent complexes, as described in accordance with The prior art can be used for phosphorescent OLEDs and as they are known in the art of organic electroluminescence, and the skilled artisan can use other phosphorescent complexes without inventive step.

In addition to the cathode, anode and one or more emitting layers, the organic electroluminescent device may contain further layers. These are selected, for example, from one or more hole injection layers, hole transport layers, hole blocking layers, electron transport layers, electron injection layers, electron blocking layers, exciton blocking layers, charge generation layers (= Charge Generation Layers, IDMC 2003, Taiwan; Session 21 OLED (5), T. Matsumoto, T. Nakada, J. Endo, K. Mori, N. Kawamura, A. Yokoi, J. Kido, Multiphoton Organic EL Device Having Charge Generation Layer ) and / or organic or inorganic p / n transitions. In addition, interlayers may be present which control the charge balance in the device. Furthermore, the layers, in particular the charge transport layers, may also be doped. The doping of the layers may be advantageous for improved charge transport. It should be noted, however, that not necessarily each of these layers must be present and the choice of layers always depends on the compounds used.

In a further preferred embodiment of the invention, the organic electroluminescent device contains a plurality of emitting layers, wherein at least one emitting layer contains at least one compound according to formula (1) or formula (2) and at least one phosphorescent emitter. More preferably, these emission layers have a total of several emission maxima between 380 nm and 750 nm, so that a total of white emission results, ie in the emitting layers different emitting compounds are used, which can fluoresce or phosphoresce and emit the blue and yellow, orange or red light , Particularly preferred are three-layer systems, ie systems with three emitting layers, wherein at least one of these layers at least one compound according to formula (1) or formula (2) and contains at least one phosphorescent emitter and wherein the three layers blue, green and orange or red emission show (for the basic structure see, for. WO 05/011013 ). The use of more than three emitting layers may also be preferred. Also suitable for white emission emitters, which have broadband emission bands and thereby show white emission.

The emissive layer containing the mixture of the compound of the formula (1) or the formula (2) and the phosphorescent emitter preferably contains between 99 and 50% by volume, preferably between 98 and 50% by volume, more preferably between 97 and 60% by volume, in particular between 95 and 85% by volume of the compound of the formula (1) or formula (2), based on the total mixture of emitter and matrix material. Accordingly, the mixture contains between 1 and 50% by volume, preferably between 2 and 50% by volume, more preferably between 3 and 40% by volume, in particular between 5 and 15% by volume of the phosphorescent emitter, based on the total mixture Emitter and matrix material.

Also preferred is the use of a plurality of matrix materials as a mixture, wherein a matrix material is selected from compounds of the formula (1) or (2). The compounds according to formula (1) and formula (2) have predominantly electron transporting properties by the electron-poor nitrogen heterocycles Ar. Therefore, when a mixture of two or more matrix materials is used, another component of the mixture is preferably a hole transporting compound. Preferred hole-conducting matrix materials are triarylamines, carbazole derivatives, e.g. B. CBP (N, N-Biscarbazolylbiphenyl) or in WO 05/039246 . US 2005/0069729 . JP 2004/288381 . EP 1205527 or WO 08/086851 disclosed carbazole derivatives, azacarbazoles, e.g. B. according to EP 1617710 . EP 1617711 . EP 1731584 . JP 2005/347160 , bipolar matrix materials, e.g. B. according to WO 07/137725 , and 9,9-diarylfluorene derivatives, e.g. B. according to the application not disclosed DE 102008017591.9 , The mixture of matrix materials may also contain more than two matrix materials. It is also possible, the matrix material according to formula (1) or formula (2) as a mixture with a to use further electron-transporting matrix material. Preferred further electron-transporting matrix materials are ketones, e.g. B. according to WO 04/093207 , Tetraaryl ketones, z. B. according to DE 102008033943.1 , Phosphine oxides, sulfoxides and sulfones, e.g. B. according to WO 05/003253 , Oligophenylenes, bipolar matrix materials, e.g. B. according to WO 07/137725 , Silane, z. B. according to WO 05/111172 , 9,9-Diarylfluorenderivate (eg according to the application not disclosed DE 102008017591.9 ), Azaboroles or boronic esters (eg according to WO 06/117052 ).

Further preferred is an organic electroluminescent device, characterized in that one or more layers are coated with a sublimation process. The materials are vapor-deposited in vacuum sublimation systems at an initial pressure of less than 10 ^-5 mbar, preferably less than 10 ^-6 mbar. It should be noted, however, that the pressure may be even lower, for example less than 10 ^-7 mbar.

Also preferred is an organic electroluminescent device, characterized in that one or more layers are coated with the OVPD (Organic Vapor Phase Deposition) method or with the aid of a carrier gas sublimation. The materials are applied at a pressure between 10 ^-5 mbar and 1 bar. A special case of this process is the OVJP (Organic Vapor Jet Printing) process, in which the materials are applied directly through a nozzle and thus structured (eg. MS Arnold et al., Appl. Phys. Lett. 2008, 92, 053301 ).

Further preferred is an organic electroluminescent device, characterized in that one or more layers of solution, such. B. by spin coating, or with any printing process, such. B. screen printing, flexographic printing or offset printing, but particularly preferably LITI (Light Induced Thermal Imaging, thermal transfer printing) or ink-jet printing (ink jet printing) can be produced. For this purpose, soluble compounds are needed. High solubility can be achieved by suitable substitution of the compounds. Not only can Solutions are applied from individual materials, but also solutions containing multiple compounds, such as matrix materials and dopants.

The organic electroluminescent device may also be fabricated as a hybrid system by applying one or more layers of solution and depositing one or more other layers. Thus, for example, it is possible to apply an emitting layer comprising a compound of the formula (1) or (2) and a phosphorescent dopant from solution and then evaporate a hole blocking layer and / or an electron transport layer in vacuo. Likewise, the emitting layer containing a compound of the formula (1) or (2) and a phosphorescent dopant may be vacuum deposited and one or more other layers may be applied from solution.

These methods are generally known to the person skilled in the art and can be applied by him without problems to organic electroluminescent devices comprising compounds of the formula (1) or (2) or the preferred embodiments listed above.

Another object of the present invention are mixtures comprising at least one phosphorescent emitter and at least one compound according to formula (1) or formula (2).

Another object of the invention are solutions containing a mixture of at least one phosphorescent emitter and at least one compound of formula (1) or formula (2) and at least one organic solvent.

Yet another object of the present invention is the use of compounds according to formula (1) or formula (2) as a matrix material for phosphorescent emitters in an organic electroluminescent device.

1. 1. Die erfindungsgemäßen organischen Elektrolumineszenzvorrichtungen weisen eine sehr hohe Effizienz auf.
2. 2. Die erfindungsgemäßen organischen Elektrolumineszenzvorrichtungen weisen gleichzeitig eine verbesserte Lebensdauer auf.
3. 3. Die erfindungsgemäßen organischen Elektrolumineszenzvorrichtungen weisen gleichzeitig eine verringerte Betriebsspannung auf.
4. 4. Die oben genannten verbesserten Eigenschaften der organischen Elektrolumineszenzvorrichtungen werden nicht nur mit tris-orthometallierten Metallkomplexen erhalten, sondern insbesondere auch mit Komplexen, welche noch einen Ketoketonat-Liganden, z. B. Acetylacetonat, enthalten. Matrixmaterialien gemäß dem Stand der Technik zeigen gerade für derartige Komplexe noch Verbesserungsbedarf in Bezug auf Effizienz, Lebensdauer und Betriebsspannung.

The organic electroluminescent devices according to the invention have the following surprising advantages over the prior art:

1. 1. The organic electroluminescent devices according to the invention have a very high efficiency.
2. 2. The organic electroluminescent devices according to the invention simultaneously have an improved lifetime.
3. 3. The organic electroluminescent devices according to the invention simultaneously have a reduced operating voltage.
4. 4. The above-mentioned improved properties of organic electroluminescent devices are obtained not only with tris-ortho metalated complexes, but in particular also with complexes which still contain a ketoketonate ligand, e.g. As acetylacetonate. Prior art matrix materials still indicate room for improvement in terms of efficiency, lifetime, and operating voltage for such complexes.

The invention will be described in more detail by the following examples without wishing to limit them thereby. The person skilled in the art, without being inventive, can produce further compounds according to the invention and use them in organic electronic devices.

Examples :

Unless stated otherwise, the following syntheses are carried out under an inert gas atmosphere in dried solvents. The starting materials can be obtained from ALDRICH (potassium fluoride (spray-dried), tri- tert -butylphosphine, palladium (II) acetate). 3-Chloro-5,6-diphenyl-1,2,4-triazine can be prepared analogously EP 577559 being represented. 2 ', 7'-di- tert- butyl-spiro-9,9'-bifluorene-2,7-bisboronic acid glycol ester can according to WO 02/077060 and 2-chloro-4,6-diphenyl-1,3,5-triazine US 5,438,138 being represented. Spiro-9,9'-bifluorene-2,7-bis (boronic acid glycol ester) can be prepared analogously to WO 02/077060 being represented.

Example 1: Synthesis of 2,7-bis (4,6-diphenyl-1,3,5-triazin-2-yl) -2 ', 7'-di- tert- butyl-spiro-9,9'-bifluorene (TRIAZIN1)

28.4 g (50.0 mmol) of 2 ', 7'-di- tert- butyl-spiro-9,9'-bifluorene-2,7-bisboronic acid glycol ester, 29.5 g (110.0 mmol) of 2-chloro-4,6-diphenyl-1 , 3,5-triazine and 44.6 g (210.0 mmol) of tripotassium phosphate are suspended in 500 ml of toluene, 500 ml of dioxane and 500 ml of water. 913 mg (3.0 mmol) of tri-o-tolylphosphine and then 112 mg (0.5 mmol) of patladium (II) acetate are added to this suspension, and the reaction mixture is refluxed for 16 h. After cooling, the organic phase is separated off, filtered through silica gel, washed three times with 200 ml of water and then concentrated to dryness. The residue is recrystallized from toluene and from dichloromethane / isopropanol and finally sublimed under high vacuum (p = 5 × 10 ^-5 mbar, T = 385 ° C.). The yield is 39.9 g (44.8 mmol), corresponding to 89.5% of theory.

Example 2: Synthesis of 2,7-bis (4,6-diphenyl-1,3,5-triazin-2-yl) -spiro-9,9'-bifluorene (TRIAZIN2)

The synthesis is carried out analogously to Example 1, the 2 ', 7'-di- tert- butyl-spiro-9,9'-bifluorene-2,7-bis (boronic acid glycol ester) being replaced by 22.8 g (50 mmol) of spiro-9, 9'-bifluorene-2,7-bis (boronic acid glycol ester) is replaced. The yield is 32.3 g (41.5 mmol), corresponding to 82.9% of theory.

Example 3: Synthesis of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) spiro-9,9'-bifluorene (TRIAZIN3)

a) Synthesis of spiro-9,9'-bifluorene-2-boronic acid

A cooled to -78 ° C solution of 71 g (180 mmol) of 2-bromo-9-spirobifluorene in 950 ml of diethyl ether is added dropwise with 73.7 ml (184 mmol) of n-butyllithium (2.5 M in hexane). The reaction mixture is 30 min. stirred at -78 ° C. It is allowed to come to room temperature, cooled again to -78 ° C and then added rapidly with a mixture of 26.4 ml (234 mmol) of trimethyl borate in 50 ml of diethyl ether. After warming to -10 ° C is hydrolyzed with 90 ml of 2 N hydrochloric acid. The organic phase is separated, washed with water, dried over sodium sulfate and concentrated to dryness. The residue is taken up in 200 ml of n-heptane, and the colorless solid is filtered off with suction, washed with n-heptane and dried in vacuo. Yield: 63 g (170 mmol), 98% of theory. Th .; Purity: 98% after ¹ H NMR.

b) Synthesis of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -spiro-9,9'-bifluorene

The synthesis is carried out analogously to Example 1, the 2 ', 7'-di- tert- butyl-spiro-9,9'-bifluorene-2,7-bis (boronic acid glycol ester) being replaced by 28 g (50 mmol) of spiro-9, 9'-bifluorene-2-boronic acid is replaced. The yield is 38 g (41.5 mmol), corresponding to 95.0% of theory.

Example 4 Production and Characterization of Organic Electroluminescent Devices Containing Triazine Compounds

Electroluminescent devices according to the invention can be used, as described, for example, in US Pat WO 05/003253 described, are shown. Here the results of different OLEDs are compared. The basic structure, the materials used, the degree of doping and their layer thicknesses are identical for better comparability.

Lochinjektionsschicht (HIL)

20 nm 2,2',7,7'-Tetrakis(di-para-tolylamino)spiro-9,9'-bifluoren

Lochtransportschicht (HTL)

20 nm NPB (N-Naphthyl-N-phenyl-4,4'-diaminobiphenyl).

Emissionsschicht (EML)

40 nm Wirtsmaterial: Spiro-Keton (SK) (Bis(9,9'-spirobifluoren-2-yl)keton) oder BAIq (1,1'-Biphenyl-4'-oxy)bis(8-hydroxy-2-methylquinolinato)aluminum) oder SK und CBP (4,4'-Bis(carbazol-9-yl)biphenyl) zu gleichen Anteilen gemischt als Vergleich oder erfindungsgemäße Verbindungen. Dotand: 15 Vol.-% Dotierung; Verbindungen siehe unten.

Lochblockierschicht (HBL)

10 nm SK (optional)

Elektronenleiter (ETL)

20 nm AlQ₃ (Tris(chinolinato)aluminium(III)).

Kathode

1 nm LiF, darauf 100 nm Al.

Examples 5-7, 12 and 15 describe prior art comparative standards in which the emission layer of the host material (or matrix material) bis (9,9'-spirobifluoren-2-yl) ketone (SK) or BAlq or a 50 : 50 Mixture SK: CBP and different guest materials (dopants) TER for red and TEG for green triplet emission. Furthermore, OLEDs containing the fluorene triazine derivatives or spirobifluorotriazine derivatives as host material are described. Analogously to the above-mentioned general method, the OLEDs are produced with the following structure:

Hole injection layer (HIL)

20 nm of 2,2 ', 7,7'-tetrakis (di-para-tolylamino) spiro-9,9'-bifluorene

Hole transport layer (HTL)

20 nm NPB (N-naphthyl-N-phenyl-4,4'-diaminobiphenyl).

Emission layer (EML)

40 nm host material: spiro-ketone (SK) (bis (9,9'-spirobifluoren-2-yl) ketone) or BAIq (1,1'-biphenyl-4'-oxy) bis (8-hydroxy-2-methylquinolinato ) aluminum) or SK and CBP (4,4'-bis (carbazol-9-yl) biphenyl) are mixed in equal proportions as a comparison or compounds of the invention. Dopant: 15 vol.% Doping; Connections see below.

Hole blocking layer (HBL)

10 nm SK (optional)

Electron conductor (ETL)

20 nm AlQ ₃ (tris (quinolinato) aluminum (III)).

cathode

1 nm LiF, then 100 nm Al.

The structures of TER-1, TER-2, TEG, SK, BAlq, CBP are shown below for the sake of clarity.

The triazines TRIAZIN2 and TRIAZIN3 used have the structures depicted in Examples 2 and 3 above.

These not yet optimized OLEDs are characterized by default; For this purpose, the electroluminescence spectra, the efficiency (measured in cd / A) as a function of the brightness, the operating voltage, calculated from current-voltage-brightness characteristics (IUL characteristic curves), and the service life are determined.

As can be seen in Tables 1 and 3, devices exhibit superior performance over the control devices SK or BAlq in measured efficiencies, voltages, and lifetimes. Furthermore, in Table 2 it can be seen that TRIAZIN2 and TRIAZIN3 are very well suited to form a mixed host with carbazole-containing host materials (here CBP). Table 1: Device results with TRIAZIN2 or TRIAZIN3 in combination with TER-1 and TER-2 as dopants Ex. EML (no HBL) Max. Eff. [cd / A] at 1000 cd / m ² Voltage [V] at 1000 cd / m ² CIE (x, y) Service life [h], initial brightness 1000 cd / m ² 5 Comp. SK: TER-1 5.6 4.9 0.69 / 0.31 3000 6 Comp. BAlq: TER-1 7.0 6.2 0.69 / 0.31 8500 7 Comp. SK: TER-2 6.8 5.6 0.66 / 12:33 14000 8th TRIAZIN2: TER-1 7.5 4.8 0.68 / 12:32 18000 9 TRIAZIN3: TER-1 7.2 5.0 0.69 / 0.31 14000 10 TRIAZIN2: TER-2 9.8 6.5 0.66 / 12:33 21000 11 TRIAZIN3: TER-2 9.0 6.5 0.66 / 12:33 18000 Ex. EML (with HBL) Max. Eff. [cd / A] at 1000 cd / m ² Voltage [V] at 1000 cd / m ² CIE (x, y) Service life [h], initial brightness 1000 cd / m ² 12 Comp. SK: CBP: TER-1 7.2 5.2 0.68 / 12:32 7000 13 TRIAZIN2: CBP: TER-1 8.0 4.7 0.68 / 12:32 25000 14 TRIAZINE3: CBP: TER-1 8.1 5.2 0.68 / 12:32 15000 Ex. EML (with HBL) Max. Eff. [cd / A] at 1000 cd / m ² Voltage [V] at 1000 cd / m ² CIE (x, y) Service life [h], initial brightness 1000 cd / m ² 15 Comp. SK: TEG 27 4.2 0.36 / 0.61 10000 16 TRIAZIN3: TEG 35 4.7 0.36 / 0.61 25000

Claims (16)

1. Organic electroluminescent device comprising, in at least one emitting layer,

   (A) at least one phosphorescent compound, and

   (B) at least one compound of the formula (1) or formula (2),

   

   

   where the following applies to the symbols and indices used:

   Ar is on each occurrence, identically or differently, a heteroaryl group selected from the group consisting of triazine, pyrazine, pyrimidine, pyridazine, pyridine, pyrazole, imidazole, oxazole, oxadiazole and thiazole, each of which may be substituted by one or more groups R¹;

   X is on each occurrence, identically or differently, a group of the formula (3), where the dashed bond in each case indicates the bonding to the two benzene rings:

   

   or X is on each occurrence, identically or differently, a divalent bridge selected from B(R¹), C(R¹)₂, Si(R¹)₂, C=C(R¹)₂, O, S, S=O, SO₂, N(R¹), P(R¹) and P(=O)R¹;

   R¹ is on each occurrence, identically or differently, H, D, F, Cl, Br, I, CHO, N(Ar¹)₂, C(=O)Ar¹, P(=O)(Ar¹)₂, S(=O)Ar¹, S(=O)₂Ar¹, CR²=CR²Ar¹, CN, NO₂, Si(R²)₃, B(OR²)₂, B(R²)₂, B(N(R²)₂)₂, OSO₂R², a straight-chain alkyl, alkoxy or thioalkoxy group having 1 to 40 C atoms or a straight-chain alkenyl or alkynyl group having 2 to 40 C atoms or a branched or cyclic alkyl, alkenyl, alkynyl, alkoxy or thioalkoxy group having 3 to 40 C atoms, each of which may be substituted by one or more radicals R², where one or more, preferably non-adjacent CH₂ groups may be replaced by R²C=CR², C=C, Si(R²)₂, Ge(R²)₂, Sn(R²)₂, C=O, C=S, C=Se, C=NR², P(=O)(R²), SO, SO₂, NR², O, S or CONR² and where one or more H atoms may be replaced by D, F, Cl, Br, I, CN or NO₂, or an aromatic or heteroaromatic ring system having 5 to 60 aromatic ring atoms, which may in each case be substituted by one or more radicals R², or an aryloxy or hetero-aryloxy group having 5 to 60 aromatic ring atoms, which may be substituted by one or more radicals R², or a combination of these systems; two or more adjacent substituents R¹ here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;

   Ar¹ is on each occurrence, identically or differently, an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may be substituted by one or more radicals R²; two radicals Ar¹ here which are bonded to the same nitrogen, phosphorus or boron atom may also be linked to one another by a single bond or a bridge selected from B(R²), C(R²)₂, Si(R²)₂, C=O, C=NR², C=C(R²)₂, O, S, S=O, SO₂, N(R²), P(R²) and P(=O)R²;

   R² is on each occurrence, identically or differently, H, D or an aliphatic, aromatic and/or heteroaromatic hydrocarbon radical having 1 to 20 C atoms, in which, in addition, H atoms may be replaced by D or F; two or more adjacent substituents R² here may also form a mono- or polycyclic, aliphatic or aromatic ring system with one another;

   n is 0 or 1;

   m is 0, 1, 2 or 3;

   o is 0, 1, 2, 3 or 4 if n = 0 and is 0, 1,2 or 3 if n=1.
2. Organic electroluminescent device according to Claim 1, characterised in that the compound of the formula (1) or formula (2) is a fluorene derivative of the formula (4) or formula (5) or a spirobifluorene derivative of the formula (6) or formula (7),

   

   

   

   

   where the symbols and indices used have the same meanings as described in Claim 1.
3. Organic electroluminescent device according to Claim 1 or 2, characterised in that the monovalent group Ar is selected from the groups of the formulae (8) to (20), where the dashed bond in each case indicates the bonding of the group to the fluorene or spirobifluorene or to the corresponding heterocyclic derivative, and R¹ has the same meaning as described in Claim 1, and in that the divalent group Ar in compounds of the formulae (2), (5) and (7) is selected from the groups of the formulae (21) to (28), where the dashed bonds in each case indicate the bonding of the group to the fluorene or spirobifluorene or to the corresponding heterocyclic derivative, and R¹ has the same meaning as described in Claim 1:

   

   

   

   

   

   
4. Organic electroluminescent device according to Claim 3, characterised in that the radical R¹ which is bonded to the groups of the formulae (8) to (28) stands, identically or differently on each occurrence, for H or D, a straight-chain alkyl or alkoxy group having 1 to 10 C atoms or a branched or cyclic alkyl or alkoxy group having 3 to 10 C atoms, each of which may be substituted by one or more radicals R², where one or more H atoms may be replaced by D or F, or for an aromatic or heteroaromatic ring system having 5 to 30 aromatic ring atoms, which may in each case be substituted by one or more radicals R², or a combination of these systems.
5. Organic electroluminescent device according to one or more of Claims 1 to 4, characterised in that the compound of the formula (1), (2) or (4) to (5) is selected from compounds of the formulae (29) to (32),

   

   

   

   

   where the symbols and indices have the same meaning as described in Claim 1, and where, for n = 0, a substituent R¹ may also be bonded in the corresponding position.
6. Organic electroluminescent device according to one or more of Claims 1 to 5, characterised in that the index m = 0, and in that the sum of the indices n + o = 0 or 1 on each benzene ring.
7. Organic electroluminescent device according to one or more of Claims 1 to 6, characterised in that the compound of the formula (1) or formula (2) is selected from compounds of the formulae (33) to (36),

   

   

   

   

   where the symbols and indices used have the meanings mentioned in Claim 1, and furthermore n + o = 0 or 1 on each benzene ring, and where, for n = 0 and o = 1, the radical R¹ may be bonded to any desired free site on the benzene ring.
8. Organic electroluminescent device according to Claim 7, characterised in that compounds of the formula (35) are selected from compounds of the formulae (37), (38) and (39),

   

   

   where the symbols used have the meanings mentioned above, and o stands, identically or differently on each occurrence, for 0 or 1.
9. Organic electroluminescent device according to one or more of Claims 1 to 8, characterised in that the phosphorescent compound is a compound which contains copper, molybdenum, tungsten, rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, silver, gold or europium, in particular a compound which contains iridium or platinum.
10. Organic electroluminescent device according to Claim 9, characterised in that the phosphorescent compound is selected from compounds of the formulae (40) to (43),

    

    

    where R¹ has the same meaning as described in Claim 1, and the following applies to the other symbols used:

    DCy is, identically or differently on each occurrence, a cyclic group which contains at least one donor atom, preferably nitrogen, carbon in the form of a carbene or phosphorus, via which the cyclic group is bonded to the metal, and which may in turn carry one or more substituents R¹; the groups DCy and CCy are connected to one another via a covalent bond;

    CCy is, identically or differently on each occurrence, a cyclic group which contains a carbon atom via which the cyclic group is bonded to the metal and which may in turn carry one or more substituents R¹;

    A is, identically or differently on each occurrence, a monoanionic, bidentate chelating ligand, preferably a diketonate ligand.
11. Organic electroluminescent device according to one or more of Claims 1 to 10, characterised in that, apart from the anode, cathode and at least one emitting layer, it comprises further layers selected from in each case one or more hole-injection layers, hole-transport layers, hole-blocking layers, electron-transport layers, electron-injection layers, electron-blocking layers, exciton-blocking layers, charge-generation layers, interlayers and/or organic or inorganic p/n junctions, where the layers may in each case also be doped.
12. Organic electroluminescent device according to one or more of Claims 1 to 11, characterised in that the emitting layer, in addition to the phosphorescent compound and the compound of the formula (1) or (2), also comprises one or more further compounds, in particular hole-transporting compounds, preferably selected from triarylamines, carbazole derivatives, azacarbazoles and bipolar matrix materials.
13. Process for the production of an organic electroluminescent device according to one or more of Claims 1 to 12, characterised in that one or more layers are produced by means of a sublimation process, by means of the OVPD (organic vapour phase deposition) process, with the aid of carrier-gas sublimation, by means of the OVJP (organic vapour jet printing) process, from solution or by means of a printing process.
14. Use of compounds of the formulae (1) and (2) as defined in Claim 1 as matrix materials for phosphorescent compounds in an organic electroluminescent device.
15. Mixture comprising at least one compound of the formula (1) or (2) as defined in Claim 1 and at least one phosphorescent compound.
16. Solution comprising a mixture according to Claim 15 and at least one organic solvent.